A quantitative method for fungal ligninolytic enzyme screening studies

Abstract

Screening is conducted to select a fungus with desired characteristics intended for various applications, e.g. bioremediation and enzyme production. A qualitative method was used in this study for screening of fungal ligninolytic enzyme activities. The fungal ligninolytic activity was correlated with its growth from the screenings to identify a suitable fungus for solid substrate fermentation. Four strains of fungi, namely, Phanerochaete chrysosporium, Pycnoporus sanguineus, Phlebia radiata and Pleurotus sajor-caju, were screened for their ligninolytic enzyme activities using guaiacol and remazol brilliant blue-R (RBB-R) as screening reagents. The screenings were conducted at both, the optimal growth temperature of each fungus and 35 • C. All the fungi, except P. radiata, showed positive guaiacol oxidation and RBB-R decolourisation activities. On the basis of the results, P. sajor-caju may be a suitable fungus for use in bioconversion of lignocellulose because it maintained guaiacol oxidation and RBB-R decolourisation activities at 35 • C. Its halo-to-colony area ratios of guaiacol oxidation and RBB-R decolourisation after 6 days were 7.0 and 2.7, respectively. In the subsequent growth study, the measured colony area was closely correlated with the dry fungal cell weight with a regression value (R 2 ) of 0.971. Thus, the colony size could be used as an indicator of fungal growth if the screening media do not significantly slow the growth of fungus. 

Polyphenolic substrates and dyes degradation by yeasts from 25 de Mayo/King George Island (Antarctica)

“…Yeast strains were inoculated in sterile Petri plates containing the supplemented medium and were incubated at 15 °C for 10 days. In the presence of guaiacol, an intense reddish‐brown colour was produced in the medium around laccase‐producing organisms (Viswanath et al ., ; Ang et al ., ). Similarly, syringaldazine was oxidized to a purple‐coloured compound in the presence of laccases (Wang et al ., ).…”

Production and Optimization of Laccase from Streptomyces lavendulae

“…The bacterial tradition became investigated for the lignolytic enzyme, laccase pastime with the aid of using guaiacol technique. A easy screening approach was accompanied in organize to hit upon laccase generating bacteria on strong media containing 0.02% guaiacol as an indicator turned into placed into effect for screening of laccase generating with the aid of bacteria, expand an extreme reddish brown colour in the medium across the bacterial colony vicinity as laccase signs (Ang et al, 2010). The appearance of the reddish brown area inside the medium resulted from the oxidative polymerization of guaiacol (Mabrouk et al, 2010).…”

Screening and induction of laccase activity in fungal species and its application in dye decolorization

“…In the presence of guaiacol, intense reddish brown color was produced in the medium around the fungal colonies and was taken as the positive reaction for the presence of laccase enzyme activity as previously reported (Coll et al, 1993;Kiiskinen et al, 2004;Vishwanath et al, 2008;Ang et al, 2010). The pale yellow color of syringaldazine is oxidized to a purple-colored compound in the presence of fungal colonies and was taken as the positive reaction for the presence of laccase enzyme activity as previously reported (Wilkołazka et al, 2002;Floch et al, 2007;Wang et al, 2010).…”

“…The main purpose of the screening is to select fungi with desired characteristics intended for various applications, example, dye decolorization and lignocellulolytic enzyme production (Ang et al, 2010 Penicillium, Trichoderma, Beauveria, Verticillium, Paecilomyces, Metarhizium and Fusarium species). In the present study, two types of screening agents were used to screen for fungal laccase activity.…”

“…As laccases oxidize various types of substrates, several different compounds have been used as indicators for laccase production. Common indicators used are guaiacol (Coll et al, 1993;Kiiskinen et al, 2004;Vishwanath et al, 2008;Ang et al, 2010), 2, 2-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) (Floch et al, 2002;Wilkołazka et al, 2002;Hao et al, 2007), syringaldazine (Floch et al, 2002;Wilkołazka et al, 2002;Wang et al, 2010) and polymeric dyes like remazol brilliant blue-R (RBB-R) (Desouza et al, 2004).…”